Continued development has lead to a further improved shears. In my Ser. No. 242,427 a triangular shaft limited the turning radius of the shears and a convex cutter with the triangular shaft did not produce a smooth rounded cut. The present improvement removes metal in a segment that may be approximately 3/8" wide and approximately 1/2" long and the upper cutter pushes downward to cut out this 3/8".times.1/2" segment square on one end and with modified elliptical shape on the leading end. Cut pieces fall by gravity and cannot interfere with further cutter action. In one embodiment the current invention comprises an upper handle, a lower handle, a replaceable upper cutter with a modified elliptical shape leading edge and square on the trailing edge, a lower cutter shaped to cuttably engage the upper cutter; a specially shaped post to secure smooth rounded cuts with a base of essentially the same width as the opening in the lower cutter and with the height being the width of the opening in the lower cutter; this post connecting the lower cutter to the body which connects to the upper handle; and a threaded pivot pin and a spring that biases apart the upper and lower handle.
The face of the upper cutter is designed to produce a shearing action as opposed to a punching action to allow use of minimum force on the handles bearing the cutters together.
The shears as we have described fills a need for hand operated shears that will operate smoothly to cut either to the right or to the left or straight ahead as well as to cut out odd shapes in metal or plastic. Further, the cutters may easily be sharpened--a file can be used to re-establish a sharp right angle cutting edge on the lower cutter while the upper cutter may be easily removed and ground. Normally there would be little need to sharpen the upper cutter as it may be made of very hard material.